Continuous thread tester



1954 G. R. ECKHARDT 2,693,108

CONTINUOUS THREAD TESTER Filed Oct. 2, 1951 2 Sheets-Sheet 1 g7 INVEN TOR.

GEORGE R. ECKHARDT BY I I 2 ATTORNEYS Nov. 2, 1954 G. R. ECKHARDT 2,593,108

CONTINUOUS THREAD TESTER Filed Oct. 2, 1951 2 Sheets-Sheet 2 v INVENTOR. GEORGE R. ECKHARDT ATTORNEYS United States Patent 2,693,108 Patented Nov. 2, 1954 CONTINUOUS THREAD TESTER George R. Eckhardt, Cliifwood, N. 3., assignor to Coats & Clark, Inc., a corporation of Delaware Application October 2, 1951, Serial No. 249,299

Claims. (Cl. 73-95) This invention relates to apparatus for testing long, continuous lengths of thread or the like.

In general, the testing is accomplished by suspending a weight in a loop of the continuously advancing thread, the weight being correlated to the theoretical strength of the thread and such as to break it if and when any spots of predetermined weakness are encountered. The apparatus is thus useful not only for testing any given thread but also for making comparative tests, on the basis of so many breaks per given length, of any number of different threads.

The object of the invention is to provide an apparatus of this character which is simple to thread up and control, which is sensitive and which can be operated at high speed.

In apparatus falling within the general outline given above, it has been proposed to use the elongation of the thread, induced by the weight and indicated by its rise and fall, to control the actual speed of the thread advancing means, either in advance of or beyond the control loop and, in some instances, to apply braking devices to the thread or yarn package itself, in order to limit the extent of movement of the weight under the varying conditions of elongation of the thread loop due to variations in the thread. But for some purposes, as for high speed testing of sewing thread, for which the apparatus to be described is especially suitable, such prior arrangements are not satisfactory from the standpoint of sensitivity, and simplicity, and also because of the changing tension and inertia conditions which result as the size of the package changes.

In accordance with the present invention, the thread is advanced or driven both ahead of and beyond the control loop, the drive means, however, operating at constant but difierent speeds; and the rise and fall of the weight is applied to control a tension device associated with the thread ahead of the first drive means. As will be brought out below, the result of the arrangement is that the function of elongating the thread is performed in part by the weight and in part by the tension device.

The invention will be understood from the following description of the accompanying drawings, in which:

Fig. l is a front elevation, in diagrammatic form, illustrating the principles of operation of a preferred form of the tester;

Fig. 2 is a side elevation, as on the line 22 of Fig- 1, of a detail of the tester; and

Fig. 3 is an elevation, in part schematic, of the drive connections of the tester.

The thread 1 passes through the tester in the direction indicated by the arrows and is first passed through an adjustable tension device. This device may be and is indicated as being of the familiar type employing a pair of opposed discs 2, 3 between which the thread passes, a biasing spring 4 and a control stem 5 movable axially to adjust the tension.

Next, the thread is preferably passed through a stationary snubber, shown as consisting of a pair of snub bars 6, 7 around which the thread is trained as indicated. The effect of the snubber is to multiply the drag applied by the tension device and hence to increase the sensitivity of the control by the tension device.

From the snubber the thread goes to the first drive means. In this preferred form such means comprises a plurality of snub rollers 8 around which the thread is trained and all of which are arranged to be driven, as by an endless chain 9 from drive motor 10 (Fig. 3).

Beyond the first drive means is the thread control loop in the bottom of which is suspended the pulley 11 and from the pulley block 12 is suspended a platform 13 to receive appropriate weights.

On the outgoing side of the loop the thread enters the second drive means, which may comprise a second and similar series of snub rollers 14 around which the thread is trained. All of these rollers are also driven, as by endless chain 15. Provision is made for varying the relative speeds of the two sets of snub rollers to ensure that the thread is taken out of the loop faster than it is fed into it. In this instance, and for simplicity of illustration, the motor drive to the second set of rollers is diagrammatically illustrated as passing through a doublecone type of adjustable speed control 16. From the second drive the thread passes to any suitable take-up bobbin or the like.

As will be understood, the weighted pulley serves to elongate the thread. Within limits, this elongation may be taken up by the second drive means, operating faster than the first; but due to the variations encountered in the thread, the pulley continually tends to rise or fall, alternately, under any fixed, relative speed of the drive means and provision is therefore made for stabilizing the pulley. As already indicated, this is accomplished by applying the rise and fall of the pulley to adjust the tension device and hence the elongation of the loop, whereby the drive means may. be permitted to operate continuously at their selected, fixed speeds.

For the above purpose a control connection is extended from the pulley block to the tension device- Such connection is shown as consisting of a cable 17 secured at its lower end to the pulley block and at its upper end to an arcuate lever 18 pivotally mounted at 19. Connected to the lever at any one of a number of points 20, so as to enable the pulley motion to be multiplied at will, is a second cable 21 which, at its lower end, is secured to the long arm 22 of a crank pivoted at 23. The short arm 24 of the crank has a pin and slot connection with the control or adjustment stem 5 of the tension device.

Thus, as the pulley block tends to fall, the control connection 17, 18, 21 actuates the crank arm 22, 24 in a direction to draw the stem 5 to the right as viewed in Fig. 2, thereby increasing the tension. Conversely, when the pulley block tends to rise, the control connection permits the tension spring 4 to move the stem 5 to the left, thereby relieving the tension. the adjustment of the tension device causes it to effect or take out more or less of the elongation of the thread, ahead of the first drive means; and thus, the tension device controls the rise and fall of the pulley by varying the amount of thread elongation left to be effected or taken out by the weighted block.

A further feature of this preferred form of the invention consists in the incorporation of a yieldable link in the control connection from the pulley block to the tension device. This link is shown as consisting of a spring 25 incorporated in cable 21. The use of such a yieldable connection results in cushioning the control action applied to the tension device and minimizes hunting. Also, sudden movements of the weight incident to sudden tension adjustments are avoided and hence the force exerted on the thread loop corresponds to the dead Weight of the applied load, undisturbed by inertia effects.

In the event of thread breakage, prompt stopping of the feed is desirable and this may be effected by or in response to the falling of the weight. For purposes of illustration, a switch 26 controlling motor circuit 27 is diagrammatically indicated 'as located below the weight in position to be opened when the weight falls upon it.

In the light of the foregoing exemplification of the principles of the invention and Without limitation to the illustrative details shown and described, the following is claimed:

Vance of the said first means; an adjustable tension de- As will be understood,

vice. associated with. the thread in advance. of the. snubber; a motion-multiplying control connection between the said weighted means and the adjustable tension device; and a yieldable link in said control connection.

2. Thread testing apparatus comprising a first means for driving afthread at constant 'spe'edfa second and following 'means for" driving the threadat, a relatively higher constant speed; weighted means engaging a loop of the. thread intermediate the said first alnd'second-v means; a stationary snubber associated. with the thread in advance of they said first means; an adjustabletension device associated with. the] thread in. advance of the snubber; and a yieldable control connection between the said weighted means and the'a'djustable tension device.

3. Thread testing apparatus comprising-a first means.- for driving'a thread. at constant speedfa segcondand' following means for driving the thread; at" a relatively. higher constant speed; weighted. means, engaging a r ap, or the threadfintermediate the'said. first; and second means; an adjustable tension device associated with the. thread; in, advance of the said first means; and a yieldablecontrol connection between. the said weighted means. and the adjustable tension device.

i 4 Thread testing apparatus comprising a first, means for driving. a. thread at constant speed; a secondand following means for driving the. thread at. a relatively higher constant speed;. weighted means engaging a; loop. of the thread intermediate the saidfirst and second means;

a stationary snnbber associated withthe thread in ad" 4 vance oi the. said. first means; an adjustable tension de= vice associated with the thread in advance of the snubber; and adjustment means-for the tension device coupled to the said weighted means for actuation in response to the rise and fall of the weighted means.

5. Thread testing apparatns comprising a first means for driving a thread at constant speed; a second and following means. for v driving the thread, at a relatively higher constant speed; weighted means engaging a loop e zn adme medi te a shfi t an o d me ns: an adjustable ltenlsion device associated with the thread in advance of the said first means; and adjustment means f h -tension. ev eec uplcd to esaid we gh ed means for actuation in response to the rise and fall of the weighted means.

References Cited in the file of this patent NITED. TA E BAIEENT J- 

